This invention relates to an astronomical, particularly solar and/or lunar, goniometric indicator designed to detect the astronomical co-ordinates of the Sun and/or the Moon and/or to provide information about time and/or position and/or intensity or intensity index of UV radiation based upon such detections, such indicator being simple, accurate, not expensive, not cumbersome and consequently easily movable.
The detection of the astronomical co-ordinates of a star or a planet, such as the Sun or the Moon, is indispensable for performing all these human activities that are connected with the position of the star itself. By way of example, not by way of limitation, agriculture and navigation activities have to always take the position of the Sun or of the Moon with respect to the Earth into account. Furthermore, in day-time, all human activities are clocked by time rolling away, which, in turn, is clocked by the Sun or Moon running through the sky.
In the following description, the astronomical goniometric indicator according to this invention will be illustrated by mainly referring to the Sun, but only by way of illustration, not by way of limitation, and it should be understood that those skilled in the art can readily modify the described indicator so as to enable similar applications to be conceived in connection with the Moon.
The three astronomical co-ordinates of the Sun that are detected with respect to the earth are: azimuth (preferably with respect to geographic South), the time angle in the equatorial plane and the altitude of the Sun.
Since very ancient times, men realised instruments, such as sun-dials, for instance, adapted to indicate the time and/or the position based upon the position of the Sun with respect to the earth. A sun-dial is a solar clock comprising an member (generally a rod), so-called gnomon, which project its own shadow or a light spot upon a suitably graduated and oriented surface.
Another instrument, known since ancient times, for detecting the position of the Sun is the sextant, as used mainly for navigation purposes.
The sextant itself, however, has certain drawbacks substantially connected with employment complexities.
Many instrument presently exist in which use is made of optics, electronics and telecommunications for detecting and/or supplying data related to astronomical co-ordinates of the Sun (and of the Moon) or depending thereon, such as the day time.
Anyhow, in many applications such as non-professional activities, it has been found that such instruments are expensive and/or complex.
In their papers xe2x80x9cCome ombra la luce: orologi solari senza gnomonexe2x80x9d, Astronomia, no. 5, September-October 1999, pages 3-6, and xe2x80x9cLight as Shadow, sun-dials without gnomonxe2x80x9d, The Compendium, Vol. 6, no. 3, September 1999, the inventors disclosed some interesting applications of a Compact Disc or CD, as a solar azimuthal clock, a solar equatorial clock, and a solar altitude clock. In fact, the inventors have shown that the diffraction phenomena occurring on the surface of a CD provided with microgrooves, when it is exposed to the Sun light, cause a thin diametral line of light that can be utilised for detecting the solar coordinates, by suitably orienting the CD and by observing it in right angle direction in a position corresponding to its centre point.
In particular, by providing a CD with a graduated scale having a radial master line and by orienting said CD such that said line is pointed to the geographical South, the indication of the Sun azimuth from the South is furnished by the angle included between said line and the diametral line of light, corresponding to the intersection of the surface of the concerned CD with the vertical plane passing through the Sun and the centre point of said CD. In this case, the CD operates as a solar azimuthal clock and can also be adapted to operate as a solar compass.
In similar way, by positioning the CD on the equatorial plane, namely slanted on the horizon by an angle equal to the co-latitude of the observation locus, and by orienting it toward South, the indication of the time angle of the Sun from South is furnished by the angle included between the South line and the diametral line of light, corresponding to the intersection of the time plane of the Sun passing through the centre point of the CD with the surface of said CD. In this case, the concerned CD operates as an equatorial solar clock and can also be adapted to operate as a solar compass.
Lastly, by positioning the CD in the vertical plane of the Sun, the diametral line of light indicates the altitude of the Sun. This case, the CD operates as an altitude based solar clock and can also be adapted to operate as an elapsed time indicator.
Anyway, the instruments disclosed in the above mentioned papers by the inventors have some shortcomings.
In the first place, the both the solar azimuthal clock and the solar altitude clock have some reading difficulties, due to the fact that the graduated scales which they are provided with include a high number of high density gathered indicator lines, as required in order to keep the position variance of the line of light in the course of the year into account.
Besides that, such instruments furnish information only in respect of the time, the altitude and the azimuth of the Sun.
The solution proposed by this invention is to be considered in this context and it is aimed at overcoming all above mentioned shortcomings.
It is an object of this invention to provide an instrument adapted to detect in simple, accurate and readily readable manner the astronomical co-ordinates of the Sun and/or of the Moon and/or to provide information about time and/or position and/or intensity or intensity index of UV radiation based upon such detection.
It is a further object of this invention to provide an instrument of the above kind, which is not expensive and adapted to be realised as a portable instrument.
It is, therefore, specific subject-matter of this invention an astronomical, particularly solar and/or lunar, goniometric indicator comprising a reflecting member and an indicating member, the reflecting member having at least one planar surface scored with substantially circular and concentric microgrooves, wherein the width and the depth of each microgroove and the distance between adjacent microgrooves are adapted to let a diametral line of diffracted and/or reflected light appear when said at least one planar surface is illuminated by a light source, the reflecting member having at least one orientation graphic sign, the indicating member including at least one graduated scale.
Also according to this invention, the microgrooves can form a planar coil or concentric circumferences.
Again according to this invention, said at least one orientation graphic sign is a line which is radial with respect to the microgrooves.
Preferably according to this invention, the reflecting member and the indicating member are incorporated in a single body. In such a case, at least one planar surface of said reflecting member can be metallised. Always in case of reflecting member and the indicating member incorporated in a single body, said at least one graduated scale may be placed on at least one corresponding planar surface of the reflecting member.
Alternatively according to this invention, the reflecting member may be transparent and may be pivoted on the indicating member. In such a case, said at least one orientation graphic sign may be a circle.
Further according to this invention, said at least one graduated scale comprising angular values and/or time values.
Again according to this invention, said astronomical goniometric indicator can be a solar goniometric indicator and said at least one graduated scale can include one or more curvilinear sectors subdivided into one or more circular sectors.
Still according to this invention, each of said circular sectors can indicate a period of the year, preferably a month of the year.
Preferably according to this invention, said at least one graduated scale includes six circular sectors indicating months of the year.
Further according to this invention, each of said curvilinear sectors can indicate a number of hours to the sunset.
Again according to this invention, each of said curvilinear sectors can indicate an intensity value or an intensity index of the UV solar radiation.
Preferably according to this invention, said reflecting member is a disc, even more preferably a Compact Disc (CD).
Still according to this invention, said reflecting member can be substantially a parallelepiped, preferably a cube, and each of its six sides has a graduated scale.
Further according to this invention, each side of said parallelepiped can include a graduated scale comprising two circular sectors each of which indicates a month of the year.
Further according to this invention, said astronomical goniometric indicator can further comprise a magnetic rod that is freely rotating when it is exposed to the magnetic field of the Earth. Such indicator, therefore, is self-orienting.
Still according to this invention, said astronomical goniometric indicator can include a graduated scale for detection of the magnetic declination of the Earth.
Still according to this invention, said reflecting member can be a disc including a metallised surface and a non-metallised surface, the latter having said magnetic rod rigidly connected thereto along a diameter of said reflecting member.
Further according to this invention, said astronomical goniometric indicator can further comprise at least one reading amplifier having a stationary member and a movable member pivotally associated thereto, said stationary member having a semicircular graduated scale whose centre point coincides with the pivotal axis, said movable member having a graduated scale extending along a circumference arc as well as mechanical guide means adapted to be coupled to said reflecting member so as to let it move along a circumference arc corresponding to the graduated scale of said movable member.
Preferably according to this invention, the graduated scale of said movable member has a radius equal to 1 m and a width equal to 15xc2x0.
Still according to this invention, said mechanical guide means include a circumference arc shaped slot adapted to receive a pin rigidly connected to said reflecting member.
Still according to this invention, said astronomical goniometric indicator can further comprise optical detector means rigidly connected to said reflecting member and adapted to detect a light signal generated by at least one planar metallised surface and to furnish the detected light signal to electronic control and processor means, said electronic control and processor means being connected to display means.
Further according to this invention, the astronomical goniometric indicator can further comprise first electromechanical means controlled by said electronic control and processor means, adapted to rotate said movable member with respect to said stationary member, as well as second electromechanical means controlled by said electronic control and processor means, adapted to move said reflecting member along the circumference arc allowed by said mechanical guide means.
Still according to this invention, said astronomical goniometric indicator can further comprises electronic clock means adapted to furnish a clock signal to said electronic control and processor means.
Again according to this invention, said astronomical goniometric indicator can also comprise further light intensity detector means coupled to said electronic control and processor means.